Connector for terminal strips

ABSTRACT

A CONNECTOR FOR MAKING CONTACT TO AN ELECTRICAL TERMINAL STRIP HAVING SPACED APART PINS ARRANGED IN ROWS. A PREFERRED EMBODIMENT OF THE CONNECTOR COMPRISES TWO RECTANGULAR PLATES OF INSULATOR MATERIAL WITH CHANNEL-SHAPED CONTACTORS OF CONDUCTIVE MATERIAL SPACED APART ALONG ONE EDGE OF EACH PLATE TO CORRESPOND TO THE SPACING OF THE PINS OF THE STRIP. A U-SHAPED BRACKET EACH OF WHOSE FLANGES HAS ONE OF THE PLATES MOUNTED THEREON MAINTAINS THE PLATES WITH THE CONTACTORS FACING OUTWARDS. A WEDGE MOUNTED BETWEEN THE CONFRONTING SURFACES OF THE PLATES IS USED TO SELECTIVELY SPREAD THE PLATES APART IN ORDER TO PUSH THE CONTACTORS AGAINST THE PINS AND ENSURE RELIABLE CONTACT.

United States Patent lnventor Joseph A. Alfiero 802 15th St, W. Babylon,N.Y. 11704 App]. No. Filed Patented Nov. 10, 1969 June 28, 1971CONNECTOR FOR TERMINAL STRIPS 3,489,986 1/1970 Frederick ABSTRACT: Aconnector for making contact to an electrical terminal strip havingspaced apart pins arranged in rows. A preferred embodiment of theconnector comprises two rectangular plates of insulator material withchannel-shaped contactors of conductive material spaced apart along oneedge of each plate to correspond to the spacing of the pins of thestrip. A U-shaped bracket each of whose flanges has one of the platesmounted thereon maintains the plates with the contactors facingoutwards. A wedge mounted between the confronting surfaces of the platesis used to selectively spread the plates apart in order to push thecontactors against the pins and ensure reliable contact.

I 1 1 I 1 I, 1 l7 25) '7 34 I Q I Patented June 28, 1971 2 Sheets-Sheet2 HG. 4A.

INVENTOR FIG. 4B.

CONNECTOR FOR TERMINAL STRIPS BACKGROUND OF THE INVENTION This inventionrelates generally to novel connecting means for making contact toelectrical terminal strips having rows of pins or lugs. Morespecifically, the invention discloses means for concurrently contactingthe pins of a terminal strip, even though the strip was not initiallydesigned to have a mating part.

One example of a terminal strip in question is the heavy duty type used,for example, by telephone companies to terminate conductors originatingat a given point (e.g., switch board) and to couple thereto variousoutput lines (e.g., telephone extensions). Another example of a terminalstrip, though more delicate, is the "platter or back plane of logic cardassemblies containing large arrays of pins used by computermanufacturers to interconnect large numbers of integrated circuits. Theterminal strips in question thus function as terminal boards. That is,each lug or pin on the strip may serve both as the termination of asignal or power line and as the distribution point for that signal orpower line.

At present, when any work has to be done on these strips, such as, forexample, connecting or disconnecting a wire to or from the strip, onlyone pin can be worked on at a time and, during the time the strip isbeing worked on any power or signal applied to the strip must be removedto prevent possible short circuits. This causes considerable down" timeand an interruption in service to the other users of the strip. Thisproblem is made more acute when it becomes necessary or desirable to dowork on some or all of the pins on the terminal strip. Thus, forexample, if most or all of the wires on one strip were to be removed andconnected to another strip, the down" time to perform the transferralwould be considerable and in addition many errors due to wrong wiresbeing removed, replaced, or mislabeled would be introduced.

It is therefore important to have connecting means which will be capableof reliably mating to all of the pins of a terminal strip. However,designing a connector to mate with all of the pins of these terminalstrips is complicated by the fact that their lugs or pins are often ofodd shapes, are often not straight and are usually corroded or oxidizedwhich makes difficult a good, low impedance electrical contact. Also,since the strips are not designed to have mating parts, the tolerancesare loose on the dimensions of the pins and the distances from pin topin.

It is therefore an object of this invention to provide means forreliably contacting concurrently a multiplicity of pins and lugs ofaterminal strip.

SUMMARY OF THE INVENTION A connector for making contact to spaced apartpins arranged in rows. The connector includes plates of insulatormaterial with contactors of conductive material spaced apart along onesurface of each plate. Mounting means are provided to hold the plateswith the contactors facing outward and also provided are means forspreading the plates apart.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings likereference characters denote like components; and,

FIG. I is a cross-sectional end view of a connector embodying theinvention mounted on a typical terminal strip;

FIG. 2 is a front view showing the mounting of contacting elements onone of the plates of the connector;

FIG. 3 is a detailed perspective view of a contactor used in conjunctionwith the connector of the invention;

FIG. 4A is a cross-sectional end view of a modified form of a connectorembodying the invention; and

FIG. 4B is a bottom view of the connector of FIG. 4A taken along line4-4.

DETAILED DESCRIPTION FIG. 1 shows a cross-sectional end view section ofthe connector mounted on a terminal strip, 10. The terminal strip 10with pins or lugs 11 is of the type discussed above and illustrates theproblems listed there. Thus, alternate pins (lugs) along the strip arenot orthogonal with respect to the horizontal presenting a problem ofmounting the connector. The pins are irregularly shaped, being hooked atthe top and flaring outwards towards the strip base, presenting aproblem of how and where to make contact to these pins. Also, some ofthese strips with which the connector is adapted to be used may be veryold and these pins may be twisted and bent. Furthermore, the pins may beoverlayed with an oxide layer (an insulator) making good electricalcontact difficult. These and other problems are overcome by connectorsembodying the invention.

The connector of FIG. 1 comprises two similar plates I2 and 14 which areconnected to the flanges 17 of U-shaped bracket 16. The plates are ofinsulator material, such as linen bakelite, which in addition to beingnonconductive is suitable to being worked (e.g., drilled and/or riveted)without breaking. The dimensions of the plates are dependent on theterminal strip to which the connector is to mate. Thus, the height ofthe plates is greater than the height of the pins on the strip and thelength of the plates is selected to correspond to the length of thestrip. The thickness of the plates is selected to ensure their rigiditywhen the connector is mated to the terminal strip and is under pressure.

Each plate is connected to one of the flanges. The bottom outer edge 34of each plate is undercut as at 35 so as to permit the contactors 40 tobe deflected as they contact the pins 11 when the plates 12 and 14 arespread apart as hereinafter described. The contactors 40 are theelements which contact the pins and are sown mounted on the lowerportion of the plates. The flanges 41, 43 of the contactors projectoutwards from the outer surfaces of the plates with the lower flanges 43contacting the pins and upper flanges 41 each having a wire 46 attachedthereto.

U-shaped bracket 16 is channel shaped and comprises a horizontal webhaving depending flanges 17 which are bent inwards. The materials usedto make the bracket should be resilient so that the depending flanges 17may be deflected as hereinafter described. The width of the web isselected to approximate the distance between the two rows of pins whileits length is substantially equal to the length of the plates. Thetapering effect of the inwardly bent flanges is such that when theplates are mounted thereon they are inclined toward each other at anangle such that the lower edges 34 are very close together. Thisfacilitates the insertion of the connector between the rows of pins onthe terminal strip and as described below permits mating the connectorwith the strip while the latter is fully wired and powered with littlefear of short circuits.

The plates 12 and 14 may be secured to the flanges 17 in any suitablemanner. In FIG. 1, the plates are shown attached to the flanges by meansof screws 18 and 20. However, the plates may be secured to the flangesby rivets or be bonded thereon by epoxy. Alternatively, the bracket 16,flanges l7, and the plates l2, 14 could be formed integrally from asingle piece of material.

Means are provided for spreading the places 12 and 14 apart so thattheir contactors 40 are forced into contact with the pins or lugs 11. Inthe embodiment illustrated, this is accomplished by the provision of awedge 32 which is operable from above the bracket 16 as hereinafterdescribed.

A threaded nut 24 is mounted on top of the web of bracket 16, and issecured thereto in any suitable manner as by soldering or pinning. Thenut is centered above a hole 25 in the web midway between the flanges17. A screw threaded shaft 26 extends between the confronting surfacesof the plates 12, 14 through the nut and web. At one end thereof is aknurled knob 28 used to rotate the shaft. The other end of the shaft 26extends through a hole 31 in a wedge 32 and tenninates in a head 30which supports wedge 32. The shaft 26 also extends through a threadednut 34 which is secured to the shaft 26 in any suitable manner. As willbe understood, rotation of the shaft 26 will raise or lower the wedge. Aplurality of shaft and nut assemblies as shown in FIG. 2 may be mountedalong the length of the connector.

As shown in FIG. 1, the wedge 32 has been forced downwardly to spreadthe plates apart to force the contactors into contact with the pins.When it is desired to place the connector in position on a terminalstrip, the wedge may be retracted by rotating shaft 26 to raise thewedge to a position contiguous to the web of bracket 16 where it has noeffect on the separation of the plates. Thereafter, the wedge may beforced downwardly in order to spread the plates apart by rotating shaft26 in the opposite direction. The wedge drives both plates equally andwith great force, if necessary, so that a high contact pressure can beachieved without distorting the alignment of the plates.

A side view of the connector showing one of the plates l2, 14 with a rowof contacts 40 mounted thereon is shown in FIG. 2. The contactors arespaced apart along the plate and since they are not in contact and theplate is of insulator material, the contactors are electrically as wellas physically isolated from each other. The contactors are secured tothe plates in any suitable manner, as by means of rivets 42, 44 forstrength, simplicity and reliability. However, the contactors could alsobe screwed'or epoxied to the plate which could be a printed circuitboard. It it also shown, as mentioned above, that more than one shaft 26may be needed to support and move the wedge bar.

A detailed sketch of a contactor is sown in FIG. 3. The contactor 40 ispreferably a U-shaped or channel-shaped element having two projecting,relatively parallel, members or flanges 41,43 separated by web 45. Theweb 45 is rectangular and flat and may have one or more centrallylocated holes 48, 49 which are used to couple the contactor to theplate. The bottom flange 43 of the contactor is notched. When the notchcontacts the pins, the shape of the notch provides a small contact areato the pins, but, there is great pressure at the point of contactresulting in a reliable electrical connection because any insulatorlayer on the pins, if present, is penetrated. The point of contactreferred to above includes the line and area contact between the pinsand the notch. The notch also serves to capture and hold the pins tomake reliable contact with pins which may have been out of alignment.The edge of the flange 43 could also be curved with the curve beingconcave or convex, straight, or slanted to either side. Thus, though theflange in the embodiment ment shown in FIG. 3 is notched and the notchshown forms an angle of less than 180 (straight angle), any projectioncapable of contacting the pins of the terminal strip to be mated issuitable. The contactor should be of conductive material and should beflexible to withstand the stresses and pressures it has to bear.Contactors made of annealed beryllium and copper (Be-Cu) which werespring tempered provided good results in an experimental unit.

The upper flange of the contactor has an eyelet 47 to which one or moreconductor wires may be connected. The maximum width of the contactor isdetermined by the spacing of the pins with the contactors being narrowerthan the minimum distance between two pins to ensure that two pinscannot be short circuited by an one contactor.

A prototype unit substantially as described in FIGS. 1, 2 and 3 designedto mate with a 1828 and C terminal strip manufactured by WesternElectric was built. Each of two plates, l.5 inches in width by l6 incheslong, had 50 contactors mounted at regular intervals thereon. Eachcontactor was approximately I.l inches long and 0.2 inches wide. Thebottom flange 43 of each contactor had a notch whose apex was at thenominal center of the flange and whose sidcn were mutuallyperpendicular. The prototype unit was mated to the above cited terminalstrip and the combination tested. All the contactors made good contactto their corresponding pins and the gripping action provided by thecontactors maintained the connector secured to the terminal strip.

In FIG. 4A and 48 a modified form of connector embodying the inventionis shown in which the wedge is moved upward to cause an outwarddeflection of the lower edge of the plates.

FIG. 4A shows a cross-sectional end view with the connector makingcontact to a lug 11 of a terminal strip. Two insulated blocks 50, 52(thick plates), having flat side surfaces on which are mountedcontactors 40 of the type discussed above, replace the relatively thinplates 12, 14 of FIG. 1. The interior surfaces of the blocks 50 and 52are beveled flaring out towards the base. A screw threaded shaft 26 isheld between the two blocks by means of bushing 56 to which are coupledflat springs 58 which are attached to the contactor block and act ashinges when the contactor blocks are spread apart. The wedge 54 ismounted at the bottom of shaft 26. When knob 28 is rotated, the wedge israised or lowered causing the contactors 40 to push against the pins orto be retracted therefrom.

FIG. 4B shows a bottom view of the connector taken along line 4-4. Thepins are shown making contact in the center of the contactors, but itshould be evident from the drawing that the notched flanges allow for awide variation in the spacing of the pins and still provide a highpressure, low impedance electrical connection.

The connector embodying the invention is thus designed to be easilyinserted between the rows of a terminal strip when the wedge isretracted to move the rows of contactors toward each other. Once theconnector is inserted between the rows, natural spring action of theU-bracket holds the connector in place. Knob(s) 28 may then be turned tospread the plates apart and to press the contactors against the pins.Also, the contactors, especially when notched, ensure that whether ornot the pins are aligned there is a high pressure contact point and thata reliable electrical connection is made.

The connector as designed may also be inserted onto a terminal stripwhich is fully powered with little fear of short circuits. Afterelectrical connection is made, all the wires on a terminal strip may betransferred to the connector with little or no interruption in serviceand the connector could then by removed from one terminal strip and madeto mate with another terminal strip with little or no interruption inservice and with little chance of error.

Another feature of the connector is that the contactors provide easyaccess to the pins. This permits the connector to be prewired andconnected to the terminal strip and the contactors on the connector maythen be used to either apply signals to the pins of the strip or else tosense signals emanating from the terminal strip.

The above-mentioned features are set forth as an indication of some ofthe advantages of the invention and are not designed to limit its scope.It will be appreciated from the illustrated and described embodimentsthat the disclosed invention provides means to contact positively andreliably a multiplicity of pins and lugs on a terminal strip even thoughthe strip was not originally designed to have a mating part.

Modifications of the disclosed embodiments, such as an increase in thenumber of plates may be made without departing from the invention asclaimed.

I claim:

1. A connector for making contact to spaced apart pins arranged in rows,comprising:

two plates of insulator material;

a plurality of contactors of electrically conductive material adapted tomake contact to said pins mounted in a row on each of said plates withthe contactors of each row spaced at regular intervals corresponding tothe spacing of said pms;

means for supporting said plates with said plates facing each other; and

means for spreading said plates apart to cause said rows of contactorsto contact the corresponding pins.

2. The combination as claimed in claim 1, wherein each of saidcontactors comprises a first section which is secured to one of saidplates and a second section which includes a flange projecting away fromsaid plates and adapted to make contact to said pins.

3. The combination as claimed in claim 2, wherein the flange included insaid second section is notched.

4. The combination as claimed in claim 2, wherein said contactors areU-shaped elements having a flange at each end of a web, wherein the webis said first section, wherein one of said two flanges is said secondsection, and wherein the other one of said two flanges is adapted forthe connection thereto of conducting means.

5. The combination as claimed in claim 4, wherein said supporting meanscomprises a U-shaped bracket having a horizontal web and two dependingflanges at opposite sides of said web;

wherein one of said plates is mounted on one of said flanges;

and

wherein the other one of said plates is mounted on the other one of saidflanges.

6. The combination as claimed in claim 5, wherein said means forspreading said plates comprises a wedge assembly including a wedgesuspended between said plates and means to move said wedge relative to.said plates to push said plates apart.

7. The combination as claimed in claim 6, wherein said wedge assemblyincludes a threaded shaft rotatably mounted in the web of said U-shapedbracket and engaging said wedge so that rotation of said shaft advancesor retracts said wedge to cause relative movement of said plates.

8. A connector, for making contact to spaced apart pins arranged inrows, comprising:

a number of plates of insulator material, each plate corresponding to adifferent one of said rows;

a plurality of contactors of electrically conductive material eachcontactor adapted to make contact to one of said pins;

means for attaching said contactors at spaced intervals corresponding tothe spacing of said pins on one surface of each of said plates;

mounting means connected to each of said plates maintaining the surfacesof said plates facing each other; and

means for selectively spreading said plates apart to cause thecontactors on the surface of each plate to contact the correspondingpins of a different one of said rows of pins.

9. The combination as claimed in claim 8, wherein the number of saidplates is two, and wherein said contactors are flexible elementscomprising a first section adapted to be mounted on said plates, asecond section adapted to make contact to said pins and a third sectionadapted to have conducting means connected thereto.

